An improved description of the heart from surface electrocardiography will aid clinical practice; a better accounting of the surface phenomena from the heart's form and behavior will add to fundamental understanding. This proposal is to examine extensively the particular use of the equivalent multipolar generator as the bridge of information transfer between the surface in both (1) the living heart and (2) parallel anatomically and physiologically advanced models of its activation and recovery. To attain these objectives we will sustain a continued rogram for the systematic collection of human body surface potential maps now with a rapid 35-electrode technique and associated instrumentation to permit practical on-line recording during changing states of eithter activation, or recovery. Thus, we may obtain comparative characterization (1) of activation by maps and such multipolar generator displays as the moving dipole and dipolar pair, and (2) of the process of recovery by maps of a new entity, the ventricular processor which closely relates to the intrinsic T wave and the ventricular gradient. Ventricular mosaic computer models of excitation and recovery will be linked to surface patterns which will permit study of variations both subepicardial and subendocardial electrical distribution patterns--the latter of especial interest in the study of fascicular block.